Socket 423 Original socket used by PIV processors. Superceded by socket 478 (see below), though there are plenty
of socket 423 CPUs and mobos out there. All future Intel PIV processors will use socket 478, so avoid this if you have any intention of upgrading the CPU.
Socket 478 New socket for PIV processors. This is the type of CPU/mobo you want to buy from this point forward.
Northwood Future .13 micron PIV processor. Current PIV processors are all .18 micron. Northwood will have a larger L2 cache and other improvements over the current PIV. The Northwoods are now scheduled to come out in January, starting at speeds of 2.2GHz and 2.0GHz. They will all be socket 478 CPUs.
These processors are likely to overclock to much higher speeds than current PIV CPUs. However, they will debut at high prices ($500 or a bit more), and are unlikely to drop to $250 or less until late spring.
In 3Q 2002, Northwood CPUs, which will initially come out in 400Mhz FSB versions, will also come out in 533Mhz FSB versions (see below), and will be distinguished with “A” and “B” suffixes. Essentially the same thing as PIII “E” and “B” CPUs.
400Mhz FSB: Current FSB rating of PIV. It is a quad-pumped 100Mhz FSB bus (meaning that four signals can travel per clock cycle). For practical purposes (i.e. multipliers, memory speed, etc), consider this to be a 100Mhz FSB. Supported by all motherboards listed.
533Mhz FSB: Future FSB rating of some future PIV. It will be a quad-pumped 133Mhz FSB bus (meaning that four signals can travel per clock cycle). For practical purposes (i.e. multipliers, memory speed, etc), consider this to be a 133Mhz FSB. Officially supported by P4X266A, status of other chipsets uncertain. Possible many of the older chipsets won’t officially support the standard, but may work at that speed anyway.
i845 Intel chipset for PIV motherboards which uses SDRAM memory (see Memory below). Since the PIV needs high-speed memory to work well, motherboards made from this chipset perform very poorly. Available in both socket 423 and 478, don’t buy either.
i850 Intel chipset for PIV motherboards which uses RDRAM memory (see Memory below). Motherboards using this chipset are relatively expensive, as is RDRAM memory, though it performs well and is worth the extra cost over i845 systems. Available in both socket 423 and 478, if you buy, buy socket 478.
SiS 645: SiS chipset for future PIV motherboards which uses DDR memory (see Memory below). Motherboard/memory combination likely to be at least $100 cheaper than an RDRAM system for now and the near future. Initial indications are it will perform a bit better than a P4X266 and usually trail an i850 board by a little bit. No current boards available. Probably will support Northwood, but check before you buy. SiS has purchased a license from Intel to produce PIV boards.
Via P4X266 Via chipset for PIV motherboards which uses DDR memory (see Memory below). It can also support SDRAM (not recommended, see i845). Motherboard/memory combination likely to be at least $100 cheaper than an RDRAM system for now and the near future. Available in both socket 423 and 478 (buy socket 478 models). Indications are it will trail a SiS645 chipset in performance by a few percentage point and an i850 by a few more than that. Initial boards now available, but chipset will be superceded shortly (see P4X266A below).
Via has not purchased a license from Intel to produce PIV boards, claiming it already had the right to do so. Intel does not agree, and both parties are suing each other.
Via P4X266A Just-announced new Via chipset for PIV motherboards which uses DDR memory (see Memory below) and will officially support 533MHz FSB (see above. Apparently the same besides that.
Via P4X333 Future Via chipset for PIV motherboards which uses DDR memory (see Memory below) and will officially support PC2700/PC 333. Will be available sometime early next year. No other substantive details.
i845-D (aka Brookdale) Future Intel chipset just like i845 except that it will support DDR (PC1600/PC200 and PC2100/PC266). Expected out January. No indications as to performance or most other advanced specifics, probably will be more expensive than SiS or Via DDR boards.
RDRAM A form of memory licensed by a company called Rambus. Operates much differently than SDRAM/DDR. Forms of RDRAM include:
SDRAM Older but still popular memory standard. Being gradually supplanted by DDR. RDRAM is its other major competitor, but has fared poorly until just recently. PC133 is current high-end standard, faster official standards not expected.
DDR A newer version of SDRAM in which two memory signals rather than one are sent per clock cycle. There are two and will shortly be three memory speeds for DDR:
What Does This All Mean?
It means you shouldn’t buy a PIV system soon. 🙂
Buying a PIV system now leaves you with some problems. The most available and cheapest motherboard is precisely the one you don’t want (the i845). The i850, while dependable, is more expensive and will be supplanted with a year. The Via DDR board is just becoming available, is likely to have some growing pains, and will be supplanted within a few months.
The SiS board looks to have longer legs, but isn’t available yet. The Intel board is a dark horse.
Any current Intel PIV system will either a) underperform or b) cost significantly more than the best AMD Athlon systems available. The Northwoods provide the potential to generally outperform what AMD is likely to have when they are introduced, but they will also be very expensive for most of the first half of 2002, and will likely only outperform the Athlon significantly if overclocked.
It is difficult to justify a PIV purchase over the next six months based solely on bang-for-the-buck. While the i850 has been a dependable chipset, it is unknown how reliable any of the DDR motherboards will be.